BREAST CANCER: SENTINEL LYMPH NODE BIOPSY LIST SERV
SCENARIO 2:
AN OBESE PATIENT
LEARNING OBJECTIVES
CASE PRESENTATION
1. Discuss indications for SLNB
2. Discuss the clinical definition of SLN
3. Discuss what constitutes an adequate
SLNB
● An obese 55 year old woman presents with clinically
suspicious nodes, and mammographic evidence of a 2 cm
primary breast cancer.
● Her BMI (body mass index) is 42.
● She has type II diabetes, essential hypertension, and
hyperlipidemia.
● A maternal aunt died from breast cancer in her 70’s.
INVESTIGATIONS
QUESTIONS FOR DISCUSSION
Technique
● STC (sterotactic core biopsy) under
mammographic guidance confirms invasive
duct carcinoma (IDC).
With regard to her axilla:
1. Is this patient eligible for SLNB or would you proceed
directly to ALND?
2. A fine needle aspiration (FNA) of a palpable lymph node
reveals benign lymphocytes. Would this alter
your decision to do a SLNB?
FOLLOW-UP
TECHNIQUE
QUESTIONS FOR DISCUSSION
The patient is taken to the operating room and
has a planned lumpectomy and SLNB.
● At the time of surgery, there is one hot node
that is also blue, and a second node that is
blue only.
● On palpation of the area, you feel a hard firm
node.
1. Which lymph nodes are the SLNs and should be removed?
2. What if there was no radioactive nodes and no visibly blue
nodes?
3. What if you removed 5 hot & blue nodes, but there was
still radioactivity greater than 10% in the axilla and there
appeared to be a least a few more distinct hot nodes in
there?
GUIDELINE INFORMATION
● “Sentinel Lymph Node Biopsy in Early-stage Breast Cancer: Guideline Recommendations”:
http://www.cancercare.on.ca/common/pages/UserFile.aspx?fileId=45870
● For key evidence, see pages 18, 27-30 of the Evidentiary Base (Section 2) of the guideline.
BREAST CANCER: SENTINEL LYMPH NODE BIOPSY LIST SERV
SCENARIO 2:
AN OBESE PATIENT
FOLLOW-UP
KEY LEARNING POINTS
Axillary Node Assessment and Biopsy
● There was consensus that a pre-operative axillary ultrasound should be obtained, as well as a FNA of nodes
felt to be suspicious on ultrasound. Suspicious nodes should have FNA, rather than proceeding directly to
ALND. There was some discussion that at some institutions, ultrasound of the axilla is not done routinely,
and if it is done, FNA of suspicious nodes may be done at a later date, resulting in delays. It was suggested
that developing a breast assessment program locally might streamline the process.
● Participants agreed that for a negative FNA, SLNB would be appropriate. If positive, one should proceed
to a full ALND.
SLNB
● Generally, there was agreement that SLNB can be performed in obese patients.
● There was discussion regarding the removal of SLN and non-SLN. Both types of lymph nodes should be
harvested. Clear labeling of nodes and indication on requisitions, before sending to pathology, is important.
Mapping Technique
○ It is recommended that the tracer be injected intradermally at the edge of the areola and that the blue dye be
injected into the subareolar area or the breast parenchyma around the tumor.
○ SLN would be any hot node (>10% of background), any blue stained node or node with a blue stained
lymphatic, and any hard suspicious palpable node.
○ Tumor replaced nodes may impair the ability of the node to take up the tracer and blue dye.
Pathology
○ There was a consensus that identification of cells micrometasteses and macrometasteses may vary
depending on pathology technique.
○ The recommended pathology technique is that excised sentinel lymph nodes be cut into sections no thicker
than 2.0 mm parallel to the longest meridian.
False Negative Rate (FNR)
○ FNR is the chance of missing disease, when disease is actually present. The denominator is not all patients
having SLNB, but only those who have positive nodes.
○ FNR of SLNB could be the result of:
- Surgical reasons – poor technique, surgeons not removing the only positive node because it was in a
non-standard location
- Pathology reasons – nodes cut too think and the disease is sitting within one part of the specimen and
not the slice/slice surface, no serial sections, missing small deposits; tissue “lost” in the cryostat due to
poor tissue handling at frozen section
- Patient reasons – obstructed lymphatics, change in flow pattern
○ The risk of FNR drops as the number of SLN increases.
○ ALND is used as the gold standard for assessing the FNR of SLNB. However, it is likely that ALND also
has a FNR.
○ One way of assessing the FNR in the general population is to determine the percent of patients having
Stage III disease since the introduction of SLNB. Using SEER data, there is one study that suggests that
the percent of patients having Stage III disease has actually increased.